The tightness and heaviness of the left thigh and the difficulty in lifting may be caused by spinal cervical spondylosis, lumbar disc herniation, cerebrovascular disease, varicose veins of the lower limbs and other diseases. 1. Spinal cord cervical spondylosis: when cervical spine lesions compress the spinal cord, weakness of the lower limbs, a feeling of stepping on cotton, difficulty in walking, etc., and the left thigh is heavy and tight and difficult to lift. 2. Lumbar intervertebral disc herniation: prolonged strain, incorrect sitting posture, etc. cause lumbar intervertebral disc prolapse, the prolapsed nucleus pulposus compresses the nerve root innervating the left lower limb, causing difficulty in walking on the left lower limb, lifting the leg, weakness, sinking and even abnormal skin sensation, such as numbness. 3. Cerebrovascular diseases: such as cerebral infarction, cerebral hemorrhage, vascular dementia, etc., which can cause cerebral nerve irritation and compression, causing lower limb motor and sensory abnormalities, heavy thighs, difficulty in lifting up and so on. 4. Lower extremity varicose veins: it refers to the superficial venous valve dysfunction of lower extremity, which is the reflux of blood in the veins, resulting in the manifestation of varicose veins. Most of the patients do not have any obvious discomfort, some patients may have heavy legs, ulcers, bleeding, superficial phlebitis and so on. Left thigh tightness and heavy lifting may also be caused by thromboembolic vasculitis and other diseases, it is recommended to consult a doctor in time to clarify the cause of the disease, targeted treatment.